Blasting apparatus



l March 25, 1930.

G. S. RICE BLASTING APPARATUS Filed sept. 28, 1927 INVENTOR WITNESSSPatented Mar. 25, 1930 UNl'lED STATES PATENT @FFME IBLASTING APPARATUSApplication led September 28, 1927. Serial No. 222,518.

cessive or dangerous temperatures are avoid-v ed. The gas used mostcommonly for this purpose is carbon dioxide, because it may be liquifiedreadily at ordinary temperatures and expansion of liquid carbon dioxidein a closed space produces enormous pressures,

" and also because it is the least toxic of the gases which may be usedand it is perfectly noncombustible.

The various means heretofore used for applying carbon dioxide as ablasting agent have not been free from objectionable features. One suchobjection is that with the apparatus now in use comparatively heavycurrents are required to set olf the blasting charge, and the risk ofsetting coal on lire or igniting fire-damp is thereby enhanced Theobject of this invention is to provide an efficient and safe meansforuse in blast-ing with compressed fluid which minimizes danger of fire orexplosion of mine gas, and which, by proper selection of the blastingagent, provides a means of blasting Without the production of toxic orcombustible gases.

To these and other ends, the invention comprises the provision of meansfor bursting a cartridge containing a blasting charge of compressedfluid, the pressure of which is insuicient to itself rupture the shellat n ormal temperatures, by chemically generatlng suicient additionalpressure in the cartridge to rupture it and thereby release the blastingcharge. For thus releasing the blasting charge, the shell is preferablyprovided with a disruptable portion whose function is to rupture at somepredetermined pressure which is in excess of that normally exerted bythe compressed fluid itself. A supplementary'valved container, adaptedto act as a gas generating chamber, may be provided Within the shell forthe purpose of supplying the additional pressure necessary to releasethe charge, and means are supplied therein for chemically generating gasand for initiating this reaction when it is desired to setoff the blast;when used, the valve in the supplementary container is of the onewaytype, and is adapted to be held shut by the pressure exerted by theblasting charge, until such time as the generated pressureexceeds thatin the main container. The valve then opens and the added pressure onthe disruptable member causes it to give Way, Whereupon the compressedfluid expands suddenly, and, owing to the elevated pressure thuscreated, produces the blast.

t Itis preferred to use carbon dioxide as the blasting medium, for thereason heretofore` stated; and likewise it is preferable to generate thesupplementary gas pressure by employing a chemical reaction involvingliberation of carbon dioxide, such for example as the reaction between acarbonate and an acid capable of liberating carbonio anhydride, the

reagents being separated in any suitable manner, and means beingprovided for permitting them to react at the desired time. It ispreferable, though not essential to the invention, to generate theadditional gas pressure in a supplementary container held Within theshell, the reason being that the use of a supplementary containerprevents destruction of the shell by the acid used, and so the shell maybe used repeatedly. Other means may be employed however to preventaction of the acid 0n the shell, such as lining it with lead,

rupture the diaphragm.

' sure 8', the detonation bein in which case the main supplementarycontainer could be dispensedwith.

rihe invention is illustrated in the accompanying drawing, whichrepresents in longitudinal central section one form of the blastingapparatus in place in a drill hole. f In this illustrative embodiment ofthe invention a cartridge comprising a cylindricalv metal casing 1 isprovided with screw threads at its ends, for receiving a renewablepressure-resisting closure member 2 and a removable, pressure-tightclosure member 3. The pressure-resisting closure comprises threadedbushings 4 and 5, and a disruptable metal disc 6 seated between them, agasket 7 being interposed between the disc and bushing 5 in order toprevent leakage. The removable closure member comprises a body portion8, threaded to screw into the casing, and is provided with a valve 10,opening into a channel 11 leading into the casing. 'Ihe innemend ofmember 8 is provided with-a shoulder portion, and removably disposedthereon is a supplementary casing 12, the free end oi' which carries anoutwardly opening flap valve 13.

Disposed Within the supplementary cas ing is a frangible container 14,which is rigidly held in place by clips 15, or in any other suitablemanner. rIhis container may be broken by detonation of a charge 16 ofmercuric fulminate, or other suitable detonator, such as lead azide,contained in a tube 17 passing through a packing gland 18 incloaccomplished by an electric current of sma l capacity passed throughtwo Wires 19, 20 which surround or are in contact with the charge 18.Prior blasting devices employing liquefied gas have required for theirdischarge, electric currents of relatively high amperage, which aredangerous because of the fire risk involved. In contradistinction tothis, I employ a current of such low capacity for setting od' thedetonator that there is no danger of igniting mine gas of lire-damp,particularly when produced by an approved electrical blasting unit.

According to one manner of operating the apparatus, a quantity of anacid strong enough to liberate carbon dioxide by reaction with asuitable substance, sulfuric acid for example, is placed in thefrangible container, which is then put in place in its clips; and in thespace surrounding is placed a substance capable of liberating carbondioxide upon treatment with acid, such for example as sodium carbonateJor sodium bicarbonate, the amounts of the reagents being such that theywill liberate suflicient gas to produce the additional pressurenecessary to Adetonatingcharge being set in place, the supplementarycont-ainer with its contents is screwed on member 8, which is thenscrewed into the main casing. The disruptable closure member' havingbeen set in place, a suitable charge or carbon dioxide is pumped intocasing 1 through valve 10, the pressure being high enough to liquefy thegas. After sufficient carbon dioxide has been introduced, valve 10 isclosed, the connections to the gas source are broken and the loadedcartridge put in place in a drill hole 21, Wooden spacers 22 and 23being used to keep the cartridges at some distance from the inner end ofthe drill hole.

The vcartridge having been packed in the hole in the usual manner, thecharge is set ed by detonating the fulminate or other detonator used,which breaks the acid container and permits the acid to react upon thecarbonate-in the supplementary casing. As this reaction proceeds, thegas pressure builds up, until it becomes higher than that of the gas inthe main casing, and the Hap valve is forced open.

'Ihe charge carried ineasingzl and the disruptable diaphragm are chosenin such relation that the additional generated pressure is sucient toburst the diaphragm and permit the liquid'carbon dioxide to expand, andin vaporizing produce the desired blasting eect.

Although it is preferred to used carbon dioxide, other gases may beused, and the term compressed fluid as used herein and in the claims isintended to pressed or liquefied gas which will produce the desiredeti'ect.` Likewise, it is not essential that the supplementary pressurebe created by generation of carbon dioxide, since other reactions mightlbe employed, the esit creates suiiicient pressure to include anycomsupplementary pressure by employing a chemical reaction and that thereaction used to produce the gas shall not be affected by the pressure.v

'An important advantage incident to the 4practice of this inventionconsists in the safe manner inwhich bursting is produced. v Thepreviously used heavy currents necessaryto produce the blast arereplaced by the low current required to set 0E the detonator, andlthebiire risks are-thereby decreased considera y.

ccording to the provisions of the patent statutes, I'l have explainedthe principle and operation of my invention, and have illus# trated anddescribed what I now'consider to represent its best embodiment. However,I desire to have it understood that, within the scope of the appendedclaims, the invention maybe practiced otherwise than as specifi-v callyillustrated and described.

I claim:` l y 1. A blasting apparatusF comprising a closed cartridgeshell openable under elevated internal pressure and containing a body ofcompressed iuid gasiable under normal tem erature and pressure, meanswithin said shel containing separated chemicals adapted l upon beingbrought into contact with each other to non-explosively generateadditional gas to add expansive force to that of said iiuid to open theshell, and means for causing said chemicals to be brought into contactwith each other.

2. A blasting apparatus comprising a cartridge shell capable ofwithstanding high internal pressure and provided with a closure capableof opening under elevated internal pressure, said shell containing acharge of compressed fluid gasiiable under normal temperature andpressure, enclosing means within said shell containing separated chem-fVicals adapted upon being brought into contact with each other tonon-explosively generate additional gas to add expansive force to thatof said fluid to open said closure, and means for causing said chemicalsto be brought into contact with each other.

3. A blasting apparatus comprising a cartridge shell capable ofwithstanding high internal pressure and provided with a closure capableof opening under elevated internal pressure, said shell containing acharge of compressed carbon dioxide, enclosing means within said shellcontaining separated chemicals adapted upon being brought into contactto non-explosively generate carbon dioxide to add expansive force to themain charge of carbon dioxide and open said closure, and means forcausing said chemicals to be brought into contact with each other.

4c. A blasting apparatus comprising a closed cartridge shell containinga body of compressed Huid gasifable under normal temperature andpressure, means including a frangible container within said shellcontaining separated chemicals adapted upon being brought into contactwith each other to nonexplosively generate additional gas to addexpansive force to that of said fluid to open the shell, and anelectrically7 dischargeable detonator for breakin said frangiblecontainer to bring said c emicals into contact with each other.

v15. A blasting cartridge comprising a shell capable of withstandinghigh internal pressure having an end provided with a disruptablediaphragm closure and containing \-a charge ofcompressed fluidgasifiable under normal temperature and pressure, a container withinsaid shell provided with separated borne by said removable closure, afrangible container disposed in said casing, electrically actuated meansfor breaking said container, chemicals disposed in said casing andcontainer adapted when in contact to generate gas under pressure, and aone-way valve in said supplementary casing for the passage of saidgenerated gas to the compressed fluid to rupture said diaphragm andpermit the iiuid to escape for blasting expansion.

In testimony whereof, I si n m name.

GEOR E RICE.

chemicals adapted to react non-explosively to u produce a gas upon beingbrought into contact, and means for bringing said chemicals into contactwith each other to add pressure to said fluid to disrupt said diaphragm.

6. A blasting cartridge comprising a shell capable of withstandingelevated internal pressure, 'a renewable disruptable diaphra and aremovable pressure-tight closure is'- posedinopposite ends of saidshelhacharge of j compressed Huid in said shell gasiliahle under normaltemperature and pressure, a casing

